(adsbygoogle = window.adsbygoogle || []).push({}); In the middle of the ocean there is a small island where there are a number of people living. They all are devoted to a very strange and specific religion, of which there is one simple rule:

"If you ever find out that you have blue eyes, you must kill yourself at midnight that night."

To get around this rule (and make sure all their friends don't kill themselves), nobody talks about the eye colour of anyone on the island, and nobody possesses any mirrors or other ways of accidentally finding out their own eye colour.

Every day when the sun is highest in the sky, all the residents of the island congregate in one area of the island so that every single one of them can see every other person on the island, and more importantly, what eye colour they have.

One day, whilst everyone is at this congregation, a foreigner arrives, and states to everyone (so that everyone can hear him) "I can see at least 1 person with blue eyes". He then leaves.

All the people are perfect logicians, if a conclusion can be logically deduced, they will do it instantly. Let us suppose that there are 100 blue eyed people on the island, and 100 brown eyed people. Knowing this, can you work out how many people kill themselves, and on which night they do it?

Before you answer, know that this is not a trick question, and the answer is logical. It doesn't depend on tricky wording or anyone lying or guessing, and it doesn't involve people doing something silly like creating a sign language or doing genetics. The foreigner is not making eye contact with anyone in particular; he's simply saying "I count at least one blue-eyed person on this island who isn't me."

Also, even though we know that there are 100 blue eyed and 100 brown eyed people on the island, this is not common knowledge to the people themselves. For example, a blue eyed person on the island cannot deduce he is blue eyed by simply counting the number of other blue eyed people; he has no idea exactly how many blue eyed people (or brown eyed people) are on the island.

And lastly, the answer is not "no one kills themselves."

Does the answer involve the island being located on the international date line?

Someone told me this IRL and I exploded.

One guy kills the rest, massive homicide; simple enough.

Every blue eye person leaves on the 100th night.

Originally posted by Fionn

In the middle of the ocean there is a small island where there are a number of people living. They all are devoted to a very strange and specific religion, of which there is one simple rule:

"If you ever find out that you have blue eyes, you must kill yourself at midnight that night."

To get around this rule (and make sure all their friends don't kill themselves), nobody talks about the eye colour of anyone on the island, and nobody possesses any mirrors or other ways of accidentally finding out their own eye colour.

Every day when the sun is highest in the sky, all the residents of the island congregate in one area of the island so that every single one of them can see every other person on the island, and more importantly, what eye colour they have.

One day, whilst everyone is at this congregation, a foreigner arrives, and states to everyone (so that everyone can hear him) "I can see at least 1 person with blue eyes". He then leaves.

All the people are perfect logicians, if a conclusion can be logically deduced, they will do it instantly. Let us suppose that there are 100 blue eyed people on the island, and 100 brown eyed people. Knowing this, can you work out how many people kill themselves, and on which night they do it?

Before you answer, know that this is not a trick question, and the answer is logical. It doesn't depend on tricky wording or anyone lying or guessing, and it doesn't involve people doing something silly like creating a sign language or doing genetics. The foreigner is not making eye contact with anyone in particular; he's simply saying "I count at least one blue-eyed person on this island who isn't me."

Also, even though we know that there are 100 blue eyed and 100 brown eyed people on the island, this is not common knowledge to the people themselves. For example, a blue eyed person on the island cannot deduce he is blue eyed by simply counting the number of other blue eyed people; he has no idea exactly how many blue eyed people (or brown eyed people) are on the island.

And lastly, the answer is not "no one kills themselves."

Originally posted by NeedaLifeSoon

Does the answer involve the island being located on the international date line?

Originally posted by Winning

Someone told me this IRL and I exploded.

Originally posted by 420

One guy kills the rest, massive homicide; simple enough.

It's complicated, but it goes something along the lines of this. Man 1 who has blue eyes looks around and sees another blue eyed person on Day 1. He thinks "If that is the only blue eyed person, he will die today." Since he is not, the blue eyed guy Man 1 saw will not kill himself, because he sees other blue eyed and assumes he is not. The next day he sees another, and every day thinks the same thing, Day 2 "Those two will die if they are the only two" Day 50 "Those 50 will die" until he has seen every other blue eyed person on the island. On Day 99. he has seen everyone but himself. Day 100 comes, he thinks "There are no more blue eyed people, I have seen 99 with blue eyes and I am certain there are no more. Perhaps I am also blue eyed." and kills himself. However, this is the tricky part. Every other islander has been going through the same thought process in his head, and on Day 100, they all realize "I must be blue eyed." and they all kill themselves. If anyone can find a loophole in my logic, feel free to point it out.

your logic was also MATT's post. :dumb:

if theres 5 ppl with blue eyes and obviously one person that has the blue eyes doesn't know it, and then they next 4 days nobody kills themselves
He would have to be the guy
Sooo
100 ppl 100th night

There is a flaw in that logic. The people on the island don't know how many blue eyed people there are in total.

If there are only 100, the person in mention would see 99 of them. Every day until Day 99 he would see another blue eyed person, and think that he has seen the final blue eyed person, and they are about to kill themselves. On Day 100, he would be unable to find another person with blue eyes, and assume the reason they aren't leaving killing themselves is he is the last blue eyed person, and he would then kill himself. Everyone else on the island with blue eyes would be thinking the same way, so therefor on Day 100 all blue eyed people would kill themselves. You have to really think hard about it, but it makes sense.



MATT's post was nothing but a link..?